Corticosteroids are categorized into: saline corticosteroids, glucocorticoids and sex hormones, and generally medicinal corticosteroids refer to glucocorticoids. Glucocorticosteroids commonly used in clinical practice include hydrocortisone, prednisone, methylprednisolone, dexamethasone, and so on. There are oral, injectable and topical dosage forms of the drugs. Glucocorticosteroids have short-acting, intermediate-acting and long-acting effects according to their duration of action. For example, hydrocortisone has a short half-life and is a short-acting hormone; methylprednisolone and prednisone have a longer half-life and can be used once a day, which is an intermediate-acting hormone; and dexamethasone has a longer half-life and is a long-acting hormone. Long-term use of glucocorticosteroids can cause sodium retention, osteoporosis, elevated blood glucose and other adverse reactions; glucocorticosteroids are contraindicated for those who are allergic to glucocorticosteroids. These drugs are widely used in patients with hypoadrenocorticism and autoimmune diseases, but should be used under the guidance of a doctor.